What contributed the MOST to Germany's decision to resume unrestricted submarine warfare against the United States prior to US entry into WWI?

A. The United States supplied munitions and money to the Allies.
B. Woodrow Wilson asked Congress for a declaration of war.
C. The United States became aware of the Zimmermann Telegram.
D. Woodrow Wilson used an executive order to arm merchant vessels.

D

Explanation:

Explanation:

The main reasons were Germany's decision to resume the policy of unrestricted submarine warfare (sinking of the Lusitania), the intercepted Zimmerman telegram in which Germany floated the idea of an alliance with Mexico, and that the balance of power was threatened.

also the answer is C

option d is correct. corroborated sources of historical evidence   is necessary to validate a claim about an event in history.

historians tend to use written sources, but audio and visual materials as well as artifacts are important objects that supply information to modern historians.

historical sources are usually divided into two categories: primary and secondary sources. depending on the historian's intent, some sources shift their designation. determining what type of sources toimplement, and the level of credibility and reliability of those sources, is a significant step in critical thinking for the historian.

explanation:

whats the question? im not quite understanding your question.